Frailty predicts greater death rate and higher costs after mitral valve surgery


Frailty is an independent predictor of morbidity, death, and increased costs after mitral valve replacement (MVR), a retrospective cohort study has determined.

Writing in The Annals of Thoracic Surgery, Amit Iyengar (Division of Cardiac Surgery, and Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA) et al say: “Among all-comers undergoing MVR in the United States, frailty was predictive of increased index hospitalisation costs, morbidity, and death. Frail patients also had more readmissions within 30 days, with increased cost and death.”

The investigators call for an increased understanding of frailty metrics among patients requiring mitral valve intervention as transcatheter interventional approaches become increasingly used. They point out that mitral valve surgery has been “underrepresented in analyses of frailty in cardiac surgery patients to date. The cohort of patients undergoing MVR are inherently sicker with more comorbidities, and the effects of frailty in this population are less clear. Thus, we sought to examine the effects of frailty on patients undergoing surgical MVR in a nationally representative cohort.”

The study was conducted using data from the Nationwide Readmissions Database (NRD) from 2010 to 2014, and evaluated the influences of frailty on outcomes and readmission rates after MVR. Frailty was defined using the Johns Hopkins Adjusted Clinical Groups frailty-defining diagnoses indicator. Multivariable logistic regression was used to determine hospital- and patient-level risk factors for readmission, postoperative complications, and death.

It found that, among 50,410 patients who underwent MVR, 7.9% met frailty criteria. Frail patients were more likely to be older, have non-private insurance, an index admission from the emergency department, and teaching hospital care (all p<0.001). Frail patients had significantly more postoperative complications (77% vs. 47%, p<0.001), more discharges to a facility (50% vs. 21%, p<0.001), and higher in-hospital mortality (12% vs 4%, p<0.001). Index hospitalisation costs were almost doubled in frail patients, and of those who survived to discharge, 30-day readmissions were more frequent (28% vs. 20%, p<0.001). Frailty independently increased the risk of index hospitalisation composite complications (adjusted odds ratio [AOR] 3.28, 95% confidence interval [CI] 2.61–4.12), in-hospital mortality (AOR 2.35, 95% CI 1.90–2.92), and 30-day readmission (AOR 1.47, 95% CI 1.20–1.78).

Limitations outlined by Iyengar and colleagues include that the study used administrative data and is subject to the accuracy of administrative coding, and that the NRD lacks patient-level data in MVR patients, including valve type, bypass times, and operative characteristics, or certain characteristics of admission, such as presentation of home versus facility, that may alter the interpretation of outcomes such as discharge disposition.

However, they point to the “underappreciated” effect that frailty has on readmission burden after surgical interventions: “As frailty affects the reserve of patients and ability to recover after insult, it follows that frailty should increase the burden of and death from readmissions, as was characterised in the current study,” they say. “The characterisation of increased readmission burden, morbidity, and cost with frail patients noted in the current study will need to be considered in the evaluation of patients for percutaneous versus open surgical intervention of the mitral valve in the future. The morbidity and cost burden from excessive readmissions in frail patients with percutaneous repair may translate to unacceptable midterm outcomes, and frailty assessments will likely have a role in identifying the optimal management strategy.”


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